Knife switch.



N0. 003,209. Patented Dec. 4, I900. J. A. WRIGHT.

KNIFE SWITCH. (Application filed May 16', 1900;,

( No Model.)

five/2221' W4. 5

TH: nonms nuns w. wow-Luna. wAsMmwoN. w. c.

UNITED STATES PATENT OFFICE.

JOHN A. WRIGHT, OF IRWIN, PENNSYLVANIA, ASSIGNOR OF ONE-HALF TO WILLIAM F. ONEILL, OF WILKINSBURG, PENNSYLVANIA.

KNIFE SWITCH.

SPECIFICATION forming part of Letters Patent No. 663,209, dated December 4, 1900.

Application filed May 16, 1900. Serial No. 16,892. (No model-Y To all whom it may concern:

Be it known that 1, JOHN A. WRIGHT, a citizen of the United States, residing at Irwin,

in the county of Westmoreland and State of Pennsylvania, have invented new and useful Improvements in Knife Switches, of which the following is specification.

One object of this invention is to provide an improved contact-post stamped in one piece from sheet metal and adapted to be bent up in such form as to make flat contact with the entire width of the switch-blade and to maintain such contact during long periods of use.

A further object is to provide the post with an integral projection for securing to the base and to provide improved means for wiring the switch from the back.

The invention consists in the novel features of construction and in the combination and arrangement of parts hereinafter fully described and claimed, and illustrated by the accompanying drawings, in which- Figure 1 is a plan view of a switch embodying my improvements. Fig. 2 is an edge view, partly in section. Fig. 3 is a cross-section on line 3 3 of Fig. 1. Fig. 4: is a detail view of one of the contact-posts. Fig. 5 is a similar view of the blank from which the post is formed. Fig. 6 illustrates means for wiring the switch from the back.

Referring to the drawings, 2 indicates the base; 3, the contact-posts; 4, the blades, and 5 the handle. Each of the contact-posts-is shaped from a blank of sheet-copper of the form shown in Fig. 5, having the elongated opposite extremities 7, which form the flat contacts for blade 4, and the central lateral extension 8, which, together with the cen- 40 tral flat portion of the post, has fiat bearing on base 2, thus providing ample room for two securing-screws 9 and 9, the latter receiving terminal binding-nut 10. The lower portions of the posts '7 are curved at 11 to form springs for resisting insertion of the blade, the metal being suitably tempered for the purpose. It will be observed that the post sides above curves 11 have slight upward convergence when the switch is open,

so that when the blade enters and forces apart sides 7 the latter flatly engage the blade its entire width. With this form of post the inward pressure of the post sides is constant at blade-hinges 4:, thus insuring permanent and perfect contact and dispensing with springwashers heretofore used on the hinge-screws.

One of sides 7 of each post is formed with small lateral projection 12, which after the post is shaped is bent transversely, thus constituting a stop for limiting the inward 6o movement of the blades, preventing them from engaging the binding-screws and holding them in such position with relation to the post as to maintain the perfect contact above referred to.

For back-wiring screw 9' is simply reversed, as shown in Fig. 6, its head bearing on the upper face of post extremity 8 and its shank uniting with the threaded bore of socket 13,

thus holding the extremity of the latter in permanent contact with the under face of extension 8, the socket at its outer end receiving the terminal binding-screw 14.

Contacts of the form here shown are most efficient, durable, and simple and may be manufactured atcomparatively small cost. Ample space is provided for two base-securing points, whereby turning of the posts on the base is rendered impossible. By referring to Fig. 5 it will be seen that the postblanks may be stamped from the sheet without a particle of waste.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A contact having one of its sides formed with a lateral projection adapted to be bent across the path of the switch-blade to form a stop, substantially as shown and described.

2. The contact-blank of sheet metal, consisting of the opposite elongated extensions 7, the central lateral extension 8, and the lateral projection 12 on one of extensions 7, substantially as shownand described.

3. A contact-blank consisting of the opposite elongated extensions 7 of corresponding length and width, and the lateral projection 8 corresponding in length to the width of extensions 7,'substantially as shown and described. v

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

JOHN A. WRIGHT.

Witnesses:

Jnssn S. WAGONER, HOMER SMITH. 

